The invention has been devised particularly, although not necessarily solely, for dewatering underground mining operations. The invention is suited to applications where very high pressures are required to pump large volumes of soiled fluids. Typically, pressures in the ordered of 2500 m water head and flow rates in the order of 200 m3/hr can be achieved.
In dewatering of underground mining operations, the water is invariably contaminated with solids. Typically, piston plunger pumps or piston diaphragm pumps are used for the pumping process. While piston pumps are effective in operation, they involve high capital costs and also high maintenance costs. The high maintenance costs arise due to the high wear rates, which result from, the arduous operating conditions of the pump valving systems which regulate the pumps intake and discharge strokes. Such systems involve pump-operating rates of some 60 to 80 cycles per minute. A further contributing factor to the high maintenance costs for piston plunger pumps is the aggressive action of the contaminated water on the reciprocating pistons and their seals.
Diaphragm pumps are not exposed to the same wear rates on the pistons and seals but nevertheless the valving systems are exposed to the same arduous conditions as diaphragm pumps also operate at some 60 to 80 cycles per minute.
There is a need for a pump which can operate at lower pumping rates and therefore be less arduous on valving associated with the pump. This requirement can be met by a collapsible chamber pump, which is a variation of a peristaltic pump. Such a pump utilises a flexible tube having a supply end and a discharge end, with a pumping chamber defined within the tube between the supply and discharge ends. Fluid pressure is employed to compress the tube, thereby urging a charge of the fluid within the pumping chamber towards the discharge end. Various proposals for such pumps are disclosed in U.S. Pat. No. 3,406,633 (Schomburg), U.S. Pat. No. 4,515,536 (van Os), U.S. Pat. No. 6,345,962 (Sutter), GB 2195149 (SB Services (Pneumatics) Ltd), WO 82/01738 (RIHA), U.S. Pat. No. 4,257,751 (Kofahl) and U.S. Pat. No. 4,886,432 (Kimberlin).
Each of these proposals utilise a flexible tube which is elastic so that it is compressible to expel the charge of fluid therein and expandable to receive a further charge of pumped fluid into the flexible tube. Each of these proposals has limitations on the maximum pressure to which the device can operate. The limitation is a result of the maximum pressure differential the flexible tube can withstand if the tube is over-compressed by the pumping fluid. If over-compressed the tube will fail by rupturing at the outlet port.
It is against this background, and the deficiencies and problems associated therewith that the present invention has developed.
The reference to the abovementioned prior art is for the purposes of background only and is not, and should not be taken as, an acknowledgement or any form of suggestion that the prior art forms part of the general knowledge in Australia.